Cyanide-bridged Coordination Polymer Research Articles

Fabrication of a one‐dimensional copper(I) cyanide bearing 4,4′‐bis(imidazoly)biphenyl) polymer as a recyclable luminescent sensing material for sensitive detection of nitrofurazone

• A new 1D Cu(I)-cyanide coordination polymer (CP) bearing 4,4′-bis(imidazoly)biphenyl synthesized. • The CP forms 2D supramolecular architecture through π•••π interactions exhibited luminescent properties. • The CP used as luminescent sensor to detect antibiotics especially nitrofurazone. A new cyanide-bridged coordination polymer with formula {[C u 1 2 (CN)( bb ) 2 ]·NO 3 ·H 2 O} n ( 1 ) (bb = 4,4′-bis(imidazoly)biphenyl), has been synthesized and characterized by microanalyses, FTIR and single crystal X-ray diffraction. The single crystal X-ray studied indicated that 1 possesses a parallel one-dimensional (1D) chain, which is woven to produce a 2D supramolecular architecture held by π···π interactions between imidazolyl rings and phenyl rings with separation of 3.873 Å and 3.789 Å, respectively. The photoluminescence sensing investigation on 1 revealed that it could be used as a recyclable fluorescent sensor for antibiotics and the polymer offers sensitive and selective detection of nitrofurazone (NFZ), with high K SV value (1.01 × 10 3 M − 1 ) and low detection limit (1.53 ppm). The plausible mechanism using which the CP exhibited sensing of antibiotics has been proposed using theoretical calculations. A new Cu(I)-cyanide coordination polymer synthesized and used as sensor for antibiotics

Node Distortion Modulation for Anisotropic Thermal Expansions of Two‐dimensional Coordination Polymers

AbstractAnisotropic negative thermal expansion is a valuable property of solid‐state materials, influencing their micromechanical and functional response. Two flexible two‐dimensional (2D) cyanide‐bridged coordination polymers (CPs) of type [Fe(salen)]2[M(CN)4] (M=MnN (FeMnN) and Pt (FePt)) were synthesized. Their anisotropic negative thermal expansions was strongly linked to relaxations of node distortions in [Fe(salen)]+ units. Comparison with the [Mn(salen)]+ analogues indicated shorter bond lengths around iron(III), due to the different electronic states. These changes of node structures resulted in FeMnN and FePt exhibiting lower and higher degrees of anisotropic thermal expansion behavior, respectively, than their Mn analogues.

Large breathing effect induced by water sorption in a remarkably stable nonporous cyanide-bridged coordination polymer.

While metal–organic frameworks (MOFs) are at the forefront of cutting-edge porous materials, extraordinary sorption properties can also be observed in Prussian Blue Analogs (PBAs) and related materials comprising extremely short bridging ligands. Herein, we present a bimetallic nonporous cyanide-bridged coordination polymer (CP) {[Mn(imH)]2[Mo(CN)8]}n (1Mn; imH = imidazole) that can efficiently and reversibly capture and release water molecules over tens of cycles without any fatigue despite being based on one of the shortest bridging ligands known – the cyanide. The sorption performance of {[Mn(imH)]2[Mo(CN)8]}n matches or even outperforms MOFs that are typically selected for water harvesting applications with perfect sorption reversibility and very low desorption temperatures. Water sorption in 1Mn is possible due to the breathing effect (accompanied by a dramatic cyanide-framework transformation) occurring in three well-defined steps between four different crystal phases studied structurally by X-ray diffraction structural analysis. Moreover, the capture of H2O by 1Mn switches the EPR signal intensity of the MnII centres, which has been demonstrated by in situ EPR measurements and enables monitoring of the hydration level of 1Mn by EPR. The sorption of water in 1Mn controls also its photomagnetic behavior at the cryogenic regime, thanks to the presence of the [MoIV(CN)8]4− photomagnetic chromophore in the structure. These observations demonstrate the extraordinary sorption potential of cyanide-bridged CPs and the possibility to merge it with the unique physical properties of this class of compounds arising from their bimetallic character (e.g. photomagnetism and long-range magnetic ordering).

Chiral porous CN-bridged coordination polymer mimicking MOF-74 and showing magnetization photoswitching.

A chiral porous cyanide-bridged framework {[MnII(L)]2[WIV(CN)8]·10H2O}n (1; L = 2,6-bis[1-(2-(N-methylamino)ethylimino)ethyl]-pyridine) showing a strong structural similarity to MOF-74 has been prepared and characterised. The crystallised water molecules can be easily removed below 60 °C, leading to a distinct crystal colour change and the activation of its photomagnetic properties - constituting the so called photomagnetic sponge behaviour of this system. The complete dehydration of 1 proceeds through a single-crystal-to-single-crystal transformation and the resulting anhydrous framework {[MnII(L)]2[WIV(CN)8]}n (1anh) was studied using single-crystal X-ray diffraction.

Pseudocapacitance-dominated high-performance and stable lithium-ion batteries from MOF-derived spinel ZnCo2O4/ZnO/C heterostructure anode.

Spinel ZnCo2O4/ZnO/C hierarchically porous structures were successfully synthesized by two-step annealing of cyanide-bridged coordination polymer precursors. Such hierarchically porous structures exhibit a regular cube structure and provide a large surface area, which provides excellent charge transport kinetics by promoting the charge transfer into the inside of the electrode materials. When used as the anode material of lithium ion batteries, the spinel ZnCo2O4/ZnO/C porous structures exhibit high capacity and excellent cycling stability with a capacity of 1100 mA h g-1 at a current density of 0.1 A g-1 and maintain 800 mA h g-1 after 400 cycles at a current density of 1 A g-1. Meanwhile, the spinel ZnCo2O4/ZnO/C porous structures also exhibit an excellent pseudocapacitive contribution ratio of 86% at a scan rate of 1 mV s-1.

A Photomagnetic Sponge: High-Temperature Light-Induced Ferrimagnet Controlled by Water Sorption.

"Converting" light energy to magnetization is the attribute of molecule-based compounds called photomagnets and is inaccessible for conventional magnetic solids. The design and synthesis of such compounds, however, is a formidable challenge, and only a few examples are known, all with rather low magnetic ordering temperatures well below the boiling point of liquid nitrogen. Herein, a cyanide-bridged coordination polymer, {[MnII(imidazole)]2[WIV(CN)8]} n, exhibiting the highest light-induced magnetic ordering temperature ever observed and a magnetic hysteresis loop up to 90 K is reported. The photomagnetic effect results from the blue light excitation (450nm) of the constituent octacyanotungstate(IV) moiety, which then couples magnetically with manganese(II), resulting in light-induced ferrimagnetic ordering. The reported coordination framework shows also outstanding water sorption properties that are strongly correlated with the photomagnetic functionality. The photoswitching observed in the anhydrous state is completely quenched by the reversible capture of water, with the fully hydrated phase becoming practically non-photomagnetic.

How to Make a Better Magnet? Insertion of Additional Bridging Ligands into a Magnetic Coordination Polymer

A three-dimensional cyanide-bridged coordination polymer based on FeII (S = 2) and NbIV (S = 1/2) {[FeII(H2O)2]2[NbIV(CN)8]·4H2O}n (Fe2Nb) was modified at the self-assembly stage by inserting an additional formate HCOO− bridge into its cyanide framework. The resulting mixed-bridged {(NH4)[(H2O)FeII-(μ-HCOO)-FeII(H2O)][NbIV(CN)8]·3H2O}n (Fe2NbHCOO) exhibited additional FeII-HCOO-FeII structural motifs connecting each of the two FeII centers. The insertion of HCOO− was possible due to the substitution of some of the aqua ligands and crystallization water molecules in the parent framework by formate anions and ammonium cations. The formate molecular bridge not only shortened the distance between FeII ions in Fe2NbHCOO from 6.609 Å to 6.141 Å, but also created additional magnetic interaction pathways between the magnetic centers, resulting in an increase in the long range magnetic ordering temperature from 43 K for Fe2Nb to 58 K. The mixed-bridged Fe2NbHCOO also showed a much broader magnetic hysteresis loop of 0.102 T, compared to 0.013 T for Fe2Nb.

Cyanide-bridged coordination polymers constructed from lanthanide ions and octacyanometallate building-blocks

Self-assembling lanthanide ions and octacyanometallate building-blocks in the presence of pyrazine-2,3-dicarboxylate acid leads to 3D dense networks.

Cyanide-Assembled d10 Coordination Polymers and Cycles: Excited State Metallophilic Modulation of Solid-State Luminescence.

The series of cyanide-bridged coordination polymers [(P2 )CuCN]n (1), [(P2 )Cu{M(CN)2 }]n (M=Cu 3, Ag 4, Au 5) and molecular tetrametallic clusters [{(P4 )MM'(CN)}2 ]2+ (MM'=Cu2 6, Ag2 7, AgCu 8, AuCu 9, AuAg 10) were obtained using the bidentate P2 and tetradentate P4 phosphane ligands (P2 =1,2-bis(diphenylphosphino)benzene; P4 =tris(2-diphenylphosphinophenyl)phosphane). All title complexes were crystallographically characterized to reveal a zig-zag chain arrangement for 1 and 3-5, whereas 6-10 possess metallocyclic frameworks with different degree of metal-metal bonding. The d10 -d10 interactions were evaluated by the quantum theory of atoms in molecules (QTAIM) computational approach. The photophysical properties of 1-10 were investigated in the solid state and supported by theoretical analysis. The emission of compounds 1 and 3-5, dominated by metal-to-ligand charge transfer (MLCT) transitions located within {CuP2 } motifs, is compatible with thermally activated delayed fluorescence (TADF) behaviour and a small energy gap between the T1 and S1 excited states. The luminescence characteristics of 6-10 are strongly dependent on the composition of the metal core; the emission band maxima vary in the range 484-650 nm with quantum efficiency reaching 0.56 (6). The origin of the emission for 6-8 and 10 at room temperature is assigned to delayed fluorescence. AuCu cluster 9, however, exhibits only phosphorescence that corresponds to theoretically predicted large value ΔE(S1 -T1 ). DFT simulation highlights a crucial impact of metallophilic bonding on the nature and energy of the observed emission, the effect being greatly enhanced in the excited state.

Self-assembly of one-dimensional nitrogen-doped hollow carbon nanoparticle chains derived from zinc hexacyanoferrate coordination polymer for lithium-ion capacitors

One-dimensional nitrogen-doped hollow carbon nanoparticle chains (CNCs) featuring bimodal pore size distribution were obtained by direct thermal pyrolysis of a three-dimensional cyanide-bridged coordination polymer precursor (zinc hexacyanoferrate) without the need for additional carbon, nitrogen, and catalyst sources. Nitrogen doping turned out to play the key role in the formation of mesoporous compartment layers and structural defects in the CNCs. Small mesopores in the walls provided high surface area for charge storage and allowed the migration of electrolyte into the compartments. Large mesopores in the hollow compartments accommodated electrolyte for easy transport of lithium ions. The commercial multiwalled carbon nanotube (CNT) electrode stored lithium ions primarily through the intercalation process, while the CNC electrode stored lithium ions through both the intercalation and adsorption processes. Thus, the CNC electrode exhibited superior supercapacitive performance than the CNT electrode. The CNC electrode with low internal resistance could deliver a high capacitance of 680Fg−1 at 1Ag−1 in the working potential range of 0.01-3.50V vs. Li/Li+, which was much better than the commercial CNT electrode (252Fg−1).

Self‐Construction from 2D to 3D: One‐Pot Layer‐by‐Layer Assembly of Graphene Oxide Sheets Held Together by Coordination Polymers

AbstractDeposition of Ni‐based cyanide bridged coordination polymer (NiCNNi) flakes onto the surfaces of graphene oxide (GO) sheets, which allows precise control of the resulting lamellar nanoarchitecture by in situ crystallization, is reported. GO sheets are utilized as nucleation sites that promote the optimized crystal growth of NiCNNi flakes. The NiCNNi‐coated GO sheets then self‐assemble and are stabilized as ordered lamellar nanomaterials. Regulated thermal treatment under nitrogen results in a Ni3C–GO composite with a similar morphology to the starting material, and the Ni3C–GO composite exhibits outstanding electrocatalytic activity and excellent durability for the oxygen reduction reaction.

Charge-Transfer Phase Transition of a Cyanide-Bridged Fe(II) /Fe(III) Coordination Polymer.

Heterometallic Prussian blue analogues are known to exhibit thermally induced charge transfer, resulting in switching of optical and magnetic properties. However, charge-transfer phase transitions have not been reported for the simplest FeFe cyanide-bridged systems. A mixed-valence Fe(II) /Fe(III) cyanide-bridged coordination polymer, {[Fe(Tp)(CN)3 ]2 Fe(bpe)⋅5 H2 O}n , which demonstrates a thermally induced charge-transfer phase transition, is described. As a result of the charge transfer during this phase transition, the high-spin state of the whole system does not change to a low-spin state. This result is in contrast to FeCo cyanide-bridged systems that exhibit charge-transfer-induced spin transitions.

Crystal structures of {[Cu(Lpn)2][Fe(CN)5(NO)]·H2O} n and {[Cu(Lpn)2]3[Cr(CN)6]2·5H2O} n [where Lpn = (R)-propane-1,2-di-amine]: two heterometallic chiral cyanide-bridged coordination polymers.

The title compounds, catena-poly[[[bis-[(R)-propane-1,2-di-amine-κ(2) N,N']copper(II)]-μ-cyanido-κ(2) N:C-[tris-(cyanido-κC)(nitroso-κN)iron(III)]-μ-cyanido-κ(2) C:N] monohydrate], {[Cu(Lpn)2][Fe(CN)5(NO)]·H2O} n , (I), and poly[[hexa-μ-cyanido-κ(12) C:N-hexa-cyanido-κ(6) C-hexa-kis-[(R)-propane-1,2-di-amine-κ(2) N,N']dichromium(III)tricopper(II)] penta-hydrate], {[Cu(Lpn)2]3[Cr(CN)6]2·5H2O} n , (II) [where Lpn = (R)-propane-1,2-di-amine, C3H10N2], are new chiral cyanide-bridged bimetallic coordination polymers. The asymmetric unit of compound (I) is composed of two independent cation-anion units of {[Cu(Lpn)2][Fe(CN)5)(NO)]} and two water mol-ecules. The Fe(III) atoms have distorted octa-hedral geometries, while the Cu(II) atoms can be considered to be penta-coordinate. In the crystal, however, the units align to form zigzag cyanide-bridged chains propagating along [101]. Hence, the Cu(II) atoms have distorted octa-hedral coordination spheres with extremely long semicoordination Cu-N(cyanido) bridging bonds. The chains are linked by O-H⋯N and N-H⋯N hydrogen bonds, forming two-dimensional networks parallel to (010), and the networks are linked via N-H⋯O and N-H⋯N hydrogen bonds, forming a three-dimensional framework. Compound (II) is a two-dimensional cyanide-bridged coordination polymer. The asymmetric unit is composed of two chiral {[Cu(Lpn)2][Cr(CN)6]}(-) anions bridged by a chiral [Cu(Lpn)2](2+) cation and five water mol-ecules of crystallization. Both the Cr(III) atoms and the central Cu(II) atom have distorted octa-hedral geometries. The coordination spheres of the outer Cu(II) atoms of the asymmetric unit can be considered to be penta-coordinate. In the crystal, these units are bridged by long semicoordination Cu-N(cyanide) bridging bonds forming a two-dimensional network, hence these Cu(II) atoms now have distorted octa-hedral geometries. The networks, which lie parallel to (10-1), are linked via O-H⋯O, O-H⋯N, N-H⋯O and N-H⋯N hydrogen bonds involving all five non-coordinating water mol-ecules, the cyanide N atoms and the NH2 groups of the Lpn ligands, forming a three-dimensional framework.

Controllable Preparation of Hierarchical ZnO Nanocages and its Oxygen Vacancy through the Nanoscale Kirkendall Process

The synthesis of ZnO with tailorable shapes and point defects is important for its potential applications. Here, a facile approach is demonstrated to prepare ZnO nanocages with controllable porous shell structures though sintering a Zn-based cyanide-bridged coordination polymer under different temperatures. The transformation of ZnCP microspheres into ZnO nanocages is based on two types of nanoscale Kirkendall effect, which are related to low temperature solid–solid interfacial oxidation and high temperature solid–gas interfacial reaction, respectively. At low temperature (around 300 °C) and before the ZnCP decomposition, the novel “hierarchical ZnO bigger nanocages embedded with smaller nanocages with 10 nm nanocrystals” can be generated. By contrast, when coming to the total decomposition of ZnCP at 800 °C, ZnO nanocages with significantly increased sizes and large cavities are generated, and large amounts of oxygen vacancies (VO) are created at the same time, leading to the dramatic increased luminescence intensities of the UV peak due to VO at 540 nm. Thus, the luminescence intensities versus defect concentration in the prepared ZnO nanocages can also be controlled by tuning the sintering temperatures.

Controlled synthesis of nanoporous nickel oxide with two-dimensional shapes through thermal decomposition of metal-cyanide hybrid coordination polymers.

The urgent need for nanoporous metal oxides with highly crystallized frameworks is motivating scientists to try to discover new preparation methods, because of their wide use in practical applications. Recent work has demonstrated that two-dimensional (2D) cyanide-bridged coordination polymers (CPs) are promising materials and appropriate for this purpose (Angew. Chem. Int. Ed.- 2013, 52, 1235). After calcination, 2D CPs can be transformed into nanoporous metal oxides with a highly accessible surface area. Here, this strategy is adopted in order to form 2D nanoporous nickel oxide (NiO) with tunable porosity and crystallinity, using trisodium citrate dihydrate as a controlling agent. The presence of trisodium citrate dihydrate plays a key role in the formation of 2D nanoflakes by controlling the nucleation rate and the crystal growth. The size of the nanoflakes gradually increases by augmenting the amount of trisodium citrate dihydrate in the reaction. After heating the as-prepared CPs in air at different temperatures, nanoporous NiO can be obtained. During this thermal treatment, organic units (carbon and nitrogen) are completely removed and only the metal content remains to take part in the formation of nanoporous NiO. In the case of large-sized 2D CP nanoflakes, the original 2D flake-shapes are almost retained, even after thermal treatment at low temperature, but they are completely destroyed at high temperature because of further crystallization in the framework. Nanoporous NiO with high surface area shows significant efficiency and interesting results for supercapacitor application.

The synthesis, crystal structure and magnetic properties of a one-dimensional terbium(III)-octacyanidomolybdate(V) assembly.

A one-dimensional cyanide-bridged coordination polymer, poly[[aquadi-μ-cyanido-κ(4)C:N-hexacyanido-κ(6)C-(dimethylformamide-κO)bis(3,4,7,8-tetramethyl-1,10-phenanthroline-κ(2)N,N')terbium(III)molybdate(V)] 4.5-hydrate], [MoTb(CN)8(C16H16N2)2(C3H7NO)(H2O)]·4.5H2O}n, has been prepared and characterized through IR spectroscopy, elemental analysis and single-crystal X-ray diffraction. The compound consists of one-dimensional chains in which cationic [Tb(tmphen)2(DMF)(H2O)](3+) (tmphen is 3,4,7,8-tetramethyl-1,10-phenanthroline) and anionic [Mo(V)(CN)8](3-) units are linked in an alternating fashion through bridging cyanide ligands. Neighbouring chains are connected by three types of hydrogen bonds (O-H···O, O-H···N and C-H···O) and by π-π interactions to form a three-dimensional supramolecular structure. In addition, magnetic investigations show that ferromagnetic interactions exist in the compound.

Crystal structure of a new modification of the cyanide-bridged copper(I) coordination compound [CuCN(bpy)] n

The hydrothermal reaction of CuCN and bpy in the presence of an octahedral cluster complex K2.75Cs1.25[Re6Se8(CN)4(OH)2]·H2O affords a cyanide-bridged chain coordination polymer [CuCN(bpy)]n (bpy — 2,2′-bipyridyl) (1). The structure is monoclinic, space group C2/c, a = 22.848(2) A, b = 7.7182(8) A, c = 14.4331(13) A, β = 127.805(2)°, V = 2010.9(3) A3, Z = 8, dx = 1.623 g/cm3. Copper atoms have a tetrahedral coordination environment formed by N atoms of the bpy molecule as well as N and C atoms of ambidentate bridging CN ligands.

Cyanide-bridged one-dimensional bimetallic complexes based on a tridentate copper(II) building block: synthesis, crystal structures and magnetic properties

The reactions of [MIII(CN)6]3− (M = Cr or Co) with CuII complexes of a tridentate schiff base [Cu(aemp)Cl] or [Cu(aemp)Ac]2 (Haemp = 2-[(2-amino-ethylimino)-methyl]-phenol) give rise to 1D cyanide-bridged bimetallic coordination polymers [Cu4(aemp)4(H2O)2][Cr(CN)6]Cl (1) and [Cu3(aemp)3(H2O)][Co(CN)6]·2H2O·MeOH (2). In complex 1, the six cyanide ligands of the [Cr(CN)6]3− moiety are involved in bridging, while in complex 2 only five cyanide ligands act as bridges to give a neutral chain. Magnetic studies reveal that complex 1 exhibits intermetallic ferromagnetic coupling, with J = 8.2 cm−1.

Phase Separation of a Hexacyanoferrate-Bridged Coordination Framework under Electrochemical Na-ion Insertion

Phase separation and transformation induced by electrochemical ion insertion are key processes in achieving efficient energy storage. Exploration of novel insertion electrode materials/reactions is particularly important to unravel the atomic/molecular-level mechanism and improve the electrochemical properties. Here, we report the unconventional phase separation of a cyanide-bridged coordination polymer, Eu[Fe(CN)6]·4H2O, under electrochemical Na-ion insertion. Detailed structural analyses performed during the electrochemical reaction revealed that, in contrast to conventional electrochemical phase separation induced by the elastic interaction between nearest neighbors, the phase separation of NaxEu[Fe(CN)6]·4H2O is due to a long-range interaction, namely, cooperative rotation ordering of hexacyanoferrates. Kolmogorov-Johnson-Mehl-Avrami analysis showed that the activation energy for the phase boundary migration in NaxEu[Fe(CN)6]·4H2O is lower than that in other conventional electrode materials such as Li(1-x)FePO4.

Synthesis, Structures and Magnetic Properties of Hydrogen-bond Directed 2D Heterobimetallic Cyanide-bridged Coordination Polymers

The complexes {[Mn(L1)(H2O)]2[Pd(CN)4]}·2CH3CN and {[Mn(L2)(H2O)]2[Pd(CN)4]}2·H2O [L1 = N,N-ethylene-bis(5-bromicsalicylideneiminate); L2 = N,N-ethylene-bis(5-methxysalicylideneiminate)] have been obtained from [Pd(CN)4]2- and the corresponding Schiff-base manganese(III) compounds. X-ray diffraction reveals that the complexes are constructed into two-dimensional supramolecular networks through intermolecular O–H…O and O–H…N hydrogen bond interactions. The magnetic susceptibilities of the two complexes reveal overall weak antiferromagnetic interactions between the adjacent Mn(III) ions.